Safety device for vaporizers



Oct. 2, 1951 o. MITCHELL 2,569,771

SAFETY DEVICE FOR VAPORIZERS Filed Jan. 12, 1946 2 Sheets-Sheet 1 Oct. 2, 1951 o. MITCHELL SAFETY DEVICE FOR VAPORIZERS 2 Sheets-Sheet :2

Filed Jan. 12, 1946 URV/LLE MITCHELL) gyW @aww (2% 3 below a certain value, the valve will open to permit gas to be discharged from the standpipe II back into the tank III to establish the required minimum pressur conditions therein.

When the thermostat 26 is satisfied, the valve 24 will be closed and the main burner will go off, leaving only the pilot burner 30 ignited. If the pilot burner 3|] fails of combustion, the safety pilot valve 29 will close. This will prevent the flow of gas to either of the burners '25 and 3B.

The present invention is concerned principally with the disposition of the valve 22. This valve may be mounted at a point convenient to the vaporized device. As shown in detail in Figs. 4 to 6, the valve is mounted on a wall of the housing for the vaporizer unit It comprises a two-part housing in the form of a valve body 36 and a support 31, between which a diaphragm 38 is clamped, the three parts being held together by suitable screws 39. The diaphragm 38 preferably is of some material such as neoprene.

The inlet 2| opens into a suitable opening 40 in the body member 36. This opening passes by a valve seat 4| into a valve chamber 42. An outlet passage 43 connects with the outlet line 23.

Within the passage 4|] of the inlet, a coil spring 44 acts, by compression, against the pipe fitting of the inlet 2| and the center of the diaphragm 38, urging the diaphragm away from the seat 4|. The support 3! has a passageway 45 therethrough, coaxial with the passage 4|. This passage receives a cup-shaped cam follower 46, in which a coil spring 41 acts'under compression against the diaphragm 38, to urge the cam follower outwardly to engage the surface of a cam 50, This cam is mounted in a two-part housing, comprising complementary side pieces 5| and 52, flanged at 53 and 54. The flangespfit on the opposite side of the housing 35 and are clamped to the housing and to the support 31 by screws 55. It will be seen that these screws thereby hold the components of the valve to the housing.

The two complementary housing portions 5| and 52 have side journal openings '51 and 58 that receive journals 59 on the oppositeends of the cam. The cam has a central opening therethrough to receive a shaft 60, to which the cam is keyed, as shown in Fig. 6. The cam has a shape such as that shown in Fig. 6. Preferably, the housing for the cam is open at its bottom.

The shaft 60 extends across the top of the tank Hi to the filler cover 6| thereon. This filler cover is typified by'a box-shaped member that is hinged by hinges B3 and 64 to the top of the tank. Preferably, the filler means areat a substantial distance from the vaporizer and from the valve 22. The filler cover covers a liquid level gauge 66, a vapor equalizing valve 61, a filler opening 68, and a pressure gauge 69.

It will be seen that the cover 6| over these filler elements has a handle 10 by which it may be raised on its hinges 63 and 64, to give access to the filler opening.

As shown more particularly in Fig. 3, the hinge 63 has a sleeve portion 12 and a sleeve portion 13 that are attached to the plate 74 fixed to the cover 6|. The other plate 15 of this hinge is secured to the tank, and it has a sleeve 16 adapted to interfit with the other two sleeves l2 and 13 to receive a conventional hinge pin 11. It'will also be seen that the rod 60 is securely attached to the sleeve 12 that is part of the cover 6| by its attachment to the plate 14 of the hinge.

When the cover 6| is raised, the rod 60 will be turned. The cam 50 has such a'shape that,

immediately after the cover 10 is slightly raised, the cam follower 46 will be moved to the left in Fig. 6 and downwardly in Fig. 5. The coil spring 41 is preferably substantially unloaded when the valve is opened. When the button 46 is moved as aforesaid, it will displace the diaphragm 38 until its central portion closes with the valve seat 4| and cuts off communication between the inlet pipe 2| and the outlet pipe 23. In so doing, it will compress the spring 44 which has less strength than the spring 41 when the button is moved to seat the Valve.

Reference to Fig. 7 will show that this closure of the valve 22 cuts off the flow of gas to the burners, which immediately become extinguished. Of course, when the burners are extinguished, the pilot safety valve 29 will close automatically. In other words, the first opening movement of the cover 6|, causes the safety valve 22 to close and shut off the flow of gas to the two burners. As a result, the filler 68 cannot be opened until the burners are completely extinguished, and no flame exists around the device that might cause an explosion from the volatile liquid discharged into the tank H1. The valve is completely shut olf by the time the lid is opened sufiiciently to insert a hose connection into the filler cap 68.

When the filling operation is completed and the lid 6| is lowered again to its closed position, the final movement will displace the cam 50 in such wise that the valve mechanism returns to the positions shown in Figs. 5 and 6, leaving communication between the inlet 2| and the outlet 23. It will be necessary to re-operate the pilot safety valve 29 and reestablish combustion at the pilot valve 30 before the main burner can re-ignite.

It will be seen that this mechanism provides a safety device that prevents the presence of flame at the burners of the vaporizer at the time fuel is supplied to the tank Hi. It will be seen that the entire operation is mechanical, and that there are, therefore, no places where sparks might be generated to ignite the fuse. The use of a diaphragm valve in this connection is a great advantage because it eliminates completely the possibility of the leakage of any fumes at the valve itself.

What is claimed is:

In a vaporizer unit for vaporizing liquid, 2. supply tank, a vaporizer chamber, an outlet pipe from the chamber, flame means associated with the vaporizer chamber, a pipe from the outlet to the flame means, a valve in said pipe, a filler opening for the tank spaced from the vaporizer, a cover movable to give access to the opening, rigid mechanical connections between the cover and the valve to close the valve and. cut off the flame means when the cover is moved as aforesaid, and a safety cut-off in the pipe between the valve and the flame means to maintain the flame pipe closed When flame is absent.

ORVILLE MITCHELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 282,037 Bean July 31, 1883 296,147 Davis Apr. 1, 1884 299,853 Ringen June 3, 1884 1,387,583 Blanchard Aug. 16, 1921 1,806,636 McCutchen May 26, 1931 

